EMEP/MSC-E Hg modeling system UNEP F&T and TF HTAP meeting, Rome 2008 EMEP/MSC-E Hg modeling system:...

Joint UNEP F&T and TF HTAP meeting, Rome 2008

EMEP/MSC-E Hg modeling system:application to TF HTAP intercomparison study

Oleg Travnikov

EMEP/MSC-E


Outline

EMEP/MSC-E Hg model description

TF HTAP Hg models intercomparison study

Modeling Hg atmospheric dispersion in the Northern Hemisphere

Intercomparison of modeling results

Major uncertainty sources of Hg modeling on a global scale


Hemispheric model (MSCE-HM-Hem)

Coverage – Northern Hemisphere

Resolution – 2.5° 2.5°Global model (MSCE-HM-Glob)

Coverage – global

Resolution – 1° 1°

EMEP/MSC-E Hg modeling system

Regional model (MSCE-HM)

Coverage – EMEP region

Resolution – 50 50 km2


Model processesAtmospheric dispersion:

Eulerian framework

Met input – ECMWF, NCEP/DOE

Met driver – SDA, GEMCVC

Atmospheric chemistry:

Gas-phase oxidation by O3, OH, Cl2

Aqueous-phase oxidation by O3, OH,

HOCl, OCL-

Aqueous-phase reduction by SO3=

No halogen chemistry in MBL

No explicit treatment of AMDE

Air-surface exchange:

Dry and wet deposition

Prescribed evasion fluxes from land

and ocean

No explicit treatment of Hg cycling

between media (atmosphere, ocean …)


TF HTAP intercomparison study

Aims of the TF HTAP model intercomparison study:

Assessment of intercontinental source-receptor

relationships

Evaluation of current models variability and uncertainties

Guidance of future model developments

Participants of Hg hemispheric/global models comparison:

MSCE-HM (EMEP/MSC-E)

GRAHM (Environment Canada, Canada)

ECHMERIT (CNR-IIA, Italy)

GEOS-Chem (Harvard University, USA)

CTM-Hg (AER, USA)


TF HTAP intercomparison study

Simulation experiment conditions:

Reference year 2001

Baseline simulation with all emission sources

Perturbation runs with 20% emission reduction in four

source regions (Europe & N. Africa, North America, East

Asia, South Asia)

North AmericaEurope & N.Africa

South Asia

East Asia


Hg emissions data

Evasion from land and ocean

Based on Lamborg et al., 2002(ca. 1800 t/y)

East Asia

839 t/y (38%)

South Asia

178 t/y (8%)

Europe

273 t/y (12%)North America

144 t/y (7%)

Other

756 t/y (35%)

Anthropogenic Hg emissions for 2000 (Pacyna et al., 2006)

North America

Europe & N.Africa

South Asia

East Asia


Evaluation of modeling results

- air concentrations- wet deposition flux

TGM concentration Hg concentration in prec.

0 1 2 3 40

1

2

3

4

Cmod

= 0.93 Cobs

Rcorr

= 0.69

M

odel, n

g/m

3

Observed, ng/m3

0 5 10 15 20 25 300

5

10

15

20

25

30

Cmod

= 1.18 Cobs

Rcorr

= 0.3

Mo

de

l, n

g/L

Observed, ng/L

Long-term simulation of Hg dispersion in the Northern Hemisphere (1990-2004)

Spatial variation (annual means)

2

1/2

2

1/2


- air concentrations- wet deposition flux

Evaluation of modeling resultsLong-term simulation of Hg dispersion in the Northern

Hemisphere (1990-2004)

Temporal variation (monthly means)

NO99 FL05

Correlation 0.41 0.40

Bias -10% -3%

Monthly statistics

0

10

20

30

40

50

янв 9

0

ию

л 9

0

янв 9

1

ию

л 9

1

янв 9

2

ию

л 9

2

янв 9

3

ию

л 9

3

янв 9

4

ию

л 9

4

янв 9

5

ию

л 9

5

янв 9

6

ию

л 9

6

янв 9

7

ию

л 9

7

янв 9

8

ию

л 9

8

янв 9

9

ию

л 9

9

янв 0

0

ию

л 0

0

янв 0

1

ию

л 0

1

янв 0

2

ию

л 0

2

янв 0

3

ию

л 0

3

янв 0

4

ию

л 0

4

Conc. in

pre

cip

itation, ng/L

Model

ObservedHg in precipitation, NO99 (Norway)

0

10

20

30

40

50

янв 9

0

ию

л 9

0

янв 9

1

ию

л 9

1

янв 9

2

ию

л 9

2

янв 9

3

ию

л 9

3

янв 9

4

ию

л 9

4

янв 9

5

ию

л 9

5

янв 9

6

ию

л 9

6

янв 9

7

ию

л 9

7

янв 9

8

ию

л 9

8

янв 9

9

ию

л 9

9

янв 0

0

ию

л 0

0

янв 0

1

ию

л 0

1

янв 0

2

ию

л 0

2

янв 0

3

ию

л 0

3

янв 0

4

ию

л 0

4

Conc. in

pre

cip

itation, ng/L

Model

Observed

Hg in precipitation, FL05 (USA)


Baseline simulation

Total deposition of Hg in the Northern Hemisphere in 2001 Average deposition flux

0

5

10

15

20

Europ

e & N

.Afri

ca

Nor

th A

mer

ica

East A

sia

South

Asia

Arctic

Nor

th A

tlant

ic

Nor

th P

acific

Depositio

n flu

x, g/k

m2/y

Evasion North America

Europe & N.Africa South Asia

East Asia Other


Perturbation runs

Decrease of Hg deposition in the Northern Hemisphere due to 20% emission reduction

in Europe in North America


Perturbation runs

Decrease of Hg deposition in the Northern Hemisphere due to 20% emission reduction

in East Asia in South Asia


Seasonal variability

Spring

Summer Fall

Winter

Decrease of Hg deposition in the Northern Hemisphere due to 20% emission reduction in Europe


Response of Hg deposition to emission reduction

Receptors Deposition decrease due to 20% emission reduction in different source regions

0

5

10

15

20

Europe&

N.Africa

North

America

East

Asia

South

Asia

Arctic North

Atlantic

North

Pacific

Receptors

Depositi

on d

ecre

ase, %

Europe & N.Africa North America

East Asia South Asia


Models intercomparison

0

5

10

15

20

Europe&

N.Africa

North

America


Receptors

Depositio

n d

ecre

ase, %



0

5

10

15

20

Europe&

N.Africa

North

America


Receptors

Depositi

on d

ecre

ase, %



0

5

10

15

20

Europe&

N.Africa

North

America


Receptors

Depositi

on d

ecre

ase, %



MSCE-HM GRAHM GEOS-Chem

Emissions (t/y) MSCE-HM GRAHM GEOS-Chem CTM-Hg

Anthropogenic 2200 (55%) 3400 (37%) 2200 (34%)

Natural 1800 (45%) 5830 (63%) 4340 (66%)

Total 4000 9230 6540

0

5

10

15

20

Europe&

N.Africa

North

America


Receptors

Depositi

on d

ecre

ase, %



CTM-Hg

Global Hg emissions used by the models


Preliminary conclusions

In general models agree in assessment of Hg deposition response to emission reduction

Hg depositions to most receptor regions (except North America) are the most sensitive to reduction of own emissions

The largest deposition response is predicted for East Asia and the smallest for North America

Total sensitivity of Hg deposition to emission reduction varies between the models and depends on relative contribution of anthropogenic emission


Sources of modeling uncertainty

Anthropogenic (incl. speciation) and natural emissions

Ignoring Hg dispersion and cycling betweendifferent media (atmosphere, ocean, soil etc.)

Hg chemistry in atmosphere and other media (reaction rates, halogen chemistry in MBL, AMDE, photoreduction in snow and seawater etc.)

Lack of measurements to evaluate the models

EMEP/MSC-E Hg modeling system UNEP F&T and TF HTAP meeting, Rome 2008 EMEP/MSC-E Hg modeling system:...

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